Fixed link for submodule

You can be redirect to submodule's page now.
name: master branch
ref id: open submodule @commit_id
url: same as ref id

![screen shot 2013-07-19 at 6 44 20](https://f.cloud.github.com/assets/259816/825280/fa0a5606-f060-11e2-9abe-fb52a5fe0c68.png)